Jersey Giant. Usually they are black but they also come in white, blue and splash. Those chicks certainly aren't black or white variety if JG but I doubt that is the breed.
You can eliminate most of those like crested birds (houdans, polish, sultans), feather legged birds (cochins), JGs are only a possibility if they are splash or blue, Anconas, Andalusians, Wyandottes, Delawares, Dominiques, partridge rocks, Most varieties of marans, Ameraucanas, Easter eggers...
What hatchery?
Knowing the breeds they include in that mix would narrow it down dramatically.
Or you could post of the breeds/varieties possibly in the mix.
Without knowing that, it could be any of maybe 40 breeds.